1. Technical Field
The present disclosure relates to a spill containment system for use with a fill pipe. More particularly, the present relation relates to a spill containment system for use in conjunction with a riser pipe of an underground storage container, such as an underground fuel storage tank, and to a method for using the same.
2. Brief Description of the Related Art
Liquid storage tanks are used for storage and distribution of a variety of liquids, such as reactants, solvents, chemical byproducts and finished materials. Underground liquid storage tanks for storing fuel are in wide spread use at gasoline service stations and fuel storage facilities. These liquid storage tanks are repetitively depleted and refilled via fill pipes or couplings located at the exterior of the storage tank. Spillage may occur during refilling, such as by tank overfilling, weak line connections, drainage from disconnected lines, faulty gaskets, leaky valve seals or the like.
Spillage of hazardous materials, such as fuel or chemicals, into the surrounding environment should be minimized. In addition to wasted liquid material, the hazardous chemicals may leach into the soil causing environmental problems, such as ground water contamination. In recognition of this threat, a variety of local, state and federal laws currently exist to regulate the use of underground liquid storage systems. For example, fill locations at some underground storage tanks are required have an overspill device capable of containing at least five gallons of liquid. Such an overspill device is located proximal a riser pipe extending from the underground storage tank to the ground above. Typically, a hose coupler or other attachment pipe is in fluid communication with the riser pipe, and is used as the port for liquid delivery or extraction. A receptacle or bucket surrounds the attachment pipe and is designed to act as a spill catch, such as for capturing any overfill or spillage resulting from transferring a load of fluid to the underground storage tank. For example, a spill receptacle may be used to catch fuel spillage when filling underground fuel storage tanks from a fuel delivery truck.
Spill containers located around fluid storage tank fill ports may be set in the ground, such as in the concrete drive of a fueling station. Concrete subsidence, or the motion of the concrete surface as it shifts downward relative to a datum, and concrete uplift, or an upward shift relative to the datum, are naturally occurring phenomena resulting from seasonal effects, extraction or dissolution of underground materials, and other causes. Since overspill devices have an opening coincident with grade level, they must accommodate movement due to uplift and subsidence. Further, since the overspill device must form a liquid tight seal between the interior of the spill receptacle and the surrounding area, a liquid tight engagement between the spill device and the riser pipe and any adjacent installation structures must also be capable of movement due to uplift and subsidence.
Given the relatively long service life of underground storage tanks, it is desirable for overspill devices installed to storage tank riser pipes to have a comparatively long service life and/or be easily replaceable. It is also desirable to minimize the effort and time required for routine maintenance tasks. For example, many riser pipes include a drop tube at the upper end of the riser pipe which may include a protection device, such as an overfill prevention device. These drop tube devices may require frequent inspection: in some jurisdictions, for example, a drop-tube mounted overfill prevention device may require monthly inspection. Moreover, the drop tube itself and/or any number of other devices may require periodic inspection. Thus, facilitation of routine maintenance to an overspill containment device should include easy access to the drop tube located in the riser pipe.
Because overspill devices are located in a wide variety of locations and climates, these devices encounter all manner of extreme weather. A cover or a manhole is one method of protecting the fill pipe and overspill containment device from precipitation and environmental degradation. In this harsh service environment, a manhole system is preferably highly weather resistant and capable of withstanding any associated rigors, such as the driving of snowplows over the manhole cover.